1. Field of the Invention
The present invention relates to polymer-surfactant compositions and methods for using such compositions, and formulations containing them in personal care applications. The formulations can be hair or skin care products such as conditioners, hair dyes, permanent waves, hair relaxers, hair bleaches, hair setting compositions, styling gels, mousses, hair gels, aftershaves, sunscreens, hand lotions, moisturizers and shaving creams.
2. Brief Description of the Prior Art
The surface properties of keratin are of interest in cosmetic science, and there has been a long-standing desire to discover ingredients which will beneficially affect the topical and bulk condition of keratinous substrates, such as hair and skin. For example, such ingredients must have adequate adherent properties, so that they are not only adsorbed initially, but are also retained on exposure to water. This property is referred to as “substantivity,” i.e., the ability of a material to be adsorbed onto keratin and to resist removal by water rinse-off.
Hair is composed of keratin, a sulfur-containing fibrous protein. The iso-electric point of keratin, and more specifically of hair, is generally in the pH range of 3.2 to 4.0. Therefore, at the pH of a typical shampoo, hair carries a net negative charge. Consequently, cationic polymers have long been used as conditioners in shampoo formulations, or as a separate treatment, in order to improve the wet and dry combability of the hair. The substantivity of the cationic polymers for negatively charged hair along with film formation facilitates detangling during wet hair combing and reducing static flyaway during dry hair combing. Cationic polymers generally also impart softness and suppleness to hair.
When cationic polymers are added to shampoos (or to skin care products such as cleaning compositions) containing anionic surfactants, formation of highly surface active association complexes generally takes place, which imparts improved foam stability to the shampoo. Maximum surface activity and foam stability, or lather, are achieved at near stoichiometric ratios of anionic surfactant to cationic polymer, where the complex is least water soluble. Generally, cationic conditioners exhibit some incompatibility at these ratios. Compatibility gives a commercially more desirable clear formulation, while incompatibility leads to a haze or precipitation, which is aesthetically less desirable in some formulations.
Hair fixative properties such as curl retention are believed to be directly related to film-forming properties of cationic polymers as well as to molecular weight, with performance generally increasing with increasing molecular weight. However, the fixative properties conferred by cationic polymers generally tend to have a reciprocal relationship to other conditioning properties, i.e., good curl retention usually means that properties such as wet combability will suffer, and vice versa.
Keratin conditioning additives generally are of three primary types: cationic polymers, proteins or protein derivatives and fatty quaternary ammonium compounds. Commonly used cationic polymers include quaternary nitrogen-containing hydroxyethyl cellulose compounds, copolymers of vinylpyrrolidone and dimethylamino-ethylmethacrylate, and amino functional polydimethyl-siloxane. Hydrolyzed animal protein has been frequently used as a keratin conditioner. Also used are natural products such as collagen and casein. Suitable quaternary ammonium compounds include such products as stearyl dimethyl ammonium chloride.
Generally, two broad areas of skin care products have been recognized as skin conditioners: emollients and humectants. Emollients generally provide improved moisture retention in the skin and plasticization/softening of the skin. Common commercial emollients are mineral oil; petrolatum; aliphatic alcohols, such as stearyl alcohol; lanolin and its derivatives; glycol stearate; and fatty acids, such as triethanolamine oleate. Humectants generally attract moisture, retard evaporation of water from the skin surface, and plasticize/soften the skin. Common commercial humectants include glycerin, propylene glycol, sorbitols and polyethylene glycols.
A desirable skin conditioner should impart at least some of the attributes of an emollient or a humectant, as well as provide improved lubricity and feel to the skin after treatment and/or reduce skin irritation caused by other components in the conditioner such as, for example, soaps, detergents, foam boosters, surfactants and perfumes. It is known by those skilled in the art that cationic polymers can be employed as skin and nail conditioners.
At times, it is also desirable that the ingredients of skin and nail care products have adequate adherent properties, so that they are not only adsorbed initially, but are also retained on exposure to water. This property, as in hair care applications, is referred to as “substantivity,” i.e., the ability of a material contacted with the keratin of skin or nails to resist removal by water rinse-off. Generally, the pH of the keratin under typical use conditions, i.e., on skin and nails, carry a net negative charge. Consequently, cationic polymers have long been used as conditioners in nail and skin care formulations. The substantivity of the cationic polymers for negatively charged skin and nails leads to film formation that facilitates lubricity, moisturizing and feel.
The skin and nail conditioning properties of lubricity, moisturizing and feel are related to the film-forming properties of the cationic polymers, as well as to molecular weight, with performance generally increasing with increasing molecular weight.
Conditioning additives comprising copolymers of dimethyldiallylammonium chloride and other monomers are well known; see, e.g., EP 308189 (with acrylamide), EP 0 308 190 and U.S. Pat. No. 4,803,071 (with hydroxyethyl cellulose). Amphoteric betaines have also been employed in cosmetic compositions; see GB 2,113,245, which discloses use of betainized dialkylaminoalkyl(meth)acrylate together with a cationic polymer.
The use of polymers of dimethyldiallylammonium chloride (DMDAAC) in the treatment of keratin is also known. See, e.g., U.S. Pat. Nos. 4,175,572 and 3,986,825. U.S. Pat. No. 5,296,218 discloses DMDAAC-based ampholyte terpolymers containing acrylamide for hair care applications, while U.S. Pat. No. 5,275,809 discloses DMDAAC-based ampholyte terpolymers containing acrylamidomethylpropane sulfonic acid for hair care uses.
U.S. Pat. No. 4,923,694 to Shih et al. discloses copolymers of vinyl pyrrolidone and (meth)acrylic cationic monomers that are useful for treating hair. These polymers are able to provide good hair styling properties at low concentrations of cationic monomer, but provide limited substantivity due to their relatively low cationic charge density. When the cationic charge density is increased, the polymers disclosed by Shih et al. become difficult to formulate with due to their decreasing compatibility with anionic surfactants.
U.S. Pat. No. 5,609,862 to Chen et al. discloses hair conditioning polymers comprised of acrylamide, acrylic acid and a cationic monomer. The conditioning polymers disclosed by Chen et al. are very compatible with anionic surfactants, but demonstrate poor compatibility with amphoteric and cationic surfactants. Further, the conditioning polymers of Chen et al. provide poor hair styling properties and only minor conditioning benefit to hair.
U.S. Pat. Nos. 5,879,670 and 6,066,315 to Melby et al. disclose conditioning polymers that include acrylic acid or acrylamidomethylpropane sulfonic acid monomers, (meth)acrylamidopropyl trimethyl ammonium chloride cationic monomers and (meth)acrylate ester nonionic monomers. The conditioning polymers of Melby et al. are difficult to formulate at low pH and do not provide good hair styling properties.
U.S. Pat. No. 4,578,267 to Salamone discloses a method of conditioning skin by applying to skin a composition which includes emollients and humectants and a sulfonic acid functional homopolymer neutralized with an alkoxylated nitrogen compound. U.S. Pat. No. 4,859,458 to Salamone et al. discloses similar compositions for use in hair conditioning. The polymers disclosed by Salamone, however, have poor substantivity to keratin substrates.
U.S. Patent Application Publication 2003/0064044 to Chen et al. discloses a composition for treating a keratin-based substrate that includes a cosmetically acceptable medium containing a water-soluble interjacent complex of a first water-soluble polymer and a second water-soluble polymer formed by polymerizing one or more water-soluble monomers in the presence of the first water-soluble polymer.
There remains a need for a polymeric conditioning additive for keratin-based substrates that provides excellent hair styling properties, as well as excellent conditioning properties to hair, skin and nails.